The Fifteenth Letter — O
It would be natural to assume that the letter “O” has its roots in the pictograph for sun. It certainly is a very clean representation and “sun-like.” However, the Phoenicians may have borrowed the spherical shape and then placed a single dot in the center, calling it “ayin,” meaning “eye.” The Egyptian hieroglyph may have been the pictograph of an eyeball or a drawing of a knotted cord with several loops showing in the cord. We aren’t sure which evolved into “ayin.” The Greeks called it “omicron” and used it for their short vowel sound. The long vowel sound was provided by “omega.”
The “O” is generally thinner at the top and the bottom of the letter, reflecting the initial creation of the letter using a flat calligraphy brush. The thickest part of the letter appearing at the one o’clock and seven o’clock positions. Even in sans serif designs there is barely perceived thinning, like the calligraphic strokes.
With credit to Allen Haley,
Upper & Lower Case magazine, a typographic centered publication last published from 1970 to 1999.